Cases have ordinarily been used for a long time in which the stick is maintained by its base in a cup-slider which is slid axially, as needed, in order to make the free end of the stick come out of the case or to return it there. This sliding can be brought about simply by moving with a finger a lateral push button that is connected to the cup-slider and that projects outward from a longitudinal slit in the case. But most often, one uses a rotary mechanism with two cooperating concentric tubes, respectively hollowed with two spiral grooves, in one case, and in the other case, with two longitudinal slits reciprocally passed through by two radial pins connected to the cup-slider.
The customer appreciates a smooth and regular operation of the rotating mechanisms, which implies minimal play between the moving elements and a controlled force of displacement. The unavoidable mechanical tolerances of the industrially molded parts which generally constitute all or almost all of the elements of these mechanisms do not allow these objectives to be fully attained. Braking devices, with or without compensation for play, are therefore used. Numerous devices have been proposed with radial braking runners inserted between the two tubes, such as those described in the French Patents Nos. 1,417,277, 2,657,238, 2,670,998, which can provide suitable braking and good centering of the tubes, but which have no effect on the axial play, which is much more difficult to control than the diametral play. In order to compensate for the axial play, cylindrical groove-frustrum-shaped circular rib assemblies have been proposed, as in the French Patent No. 2,169,557, which can provide good axial fixing but without elasticity, therefore to the detriment of the regular and smooth manipulation of the mechanism.